ANN ARBOR – Shortly after 10 p.m. on Thursday night, social media posts by residents on Ann Arbor’s northside began flowing in asking the same question: “Did anyone hear that loud boom?”
Residents took to Twitter, Nextdoor and various local Facebook groups to seek more information on a blast that shook nearby houses and was heard as far as Packard and Platt.
Ann Arbor Fire Chief Mike Kennedy said his department responded to what was initially described as an explosion at the Busch’s grocery store across the street from the blast site.
Upon arrival, they discovered that the blast had occurred on a grassy University of Michigan property where the school’s student rocket club is known to carry out tests from a shipping container.
“We had no clue the sophistication or the hazard of what this group was doing prior to last night,” said Kennedy. “The fuel was ethanol, helium, oxygen and nitrogen.”
Kennedy said firefighters found an ethanol fire on the floor of the container, which they put out. The concussion from the incident blasted over pressurized gas cylinders, so firefighters had to turn off all the cylinders and conduct gas monitoring before declaring the area safe.
“Fortunately, it was raining last night,” said Kennedy. “Two weeks ago the field would have taken off.”
Ann Arbor City Councilmember Linh Song, who lives near the testing site, said the blast shook the windows of her house.
“It was so loud,” said Song. “I’m just south of that parcel. Neighbors were messaging me and we were looking outside our doors and trying to figure out what it was and then we heard sirens. I thought it was an explosion or maybe an accident off of US-23 and Plymouth.”
She quickly went onto the scene to see what had happened and was relieved to discover that no one was hurt at the site.
“I’ve been here almost 20 years and to my knowledge there haven’t been concerns before,” said Song. “It was always interesting to see students working on the site. We’ve been aware that they’ve been there for a while.”
Song said that the neighborhood is home to multiple scientists and that experiments aren’t unusual in the area, but this was the first time a blast was felt by nearby residents.
According to U-M’s engineering department, the students notified the Ann Arbor fire and police departments and U-M’s Division of Public Safety and Security on Thursday morning that they were going to be conducting tests that night.
“The team has permission to operate at that test site from the University Planner, the City of Ann Arbor and DPSS. U-M’s Environment, Health and Safety Department (EHS) routinely reviews the students’ procedures every time there is a change to standard operating procedure, and they are conducting a thorough investigation of the incident,” Michigan Engineering news director Nicole Casal Moore wrote in an email to A4, noting that the EHS review includes fire safety.
Associate professor of aerospace engineering at U-M and faculty advisor to the rocket club, Mirko Gamba, said that all protocols were in place at the time the combustion occurred, and that an investigation into the cause of the blast is underway.
“It was an anomaly between the shutdown process that caused the fuel to be spilled outside the main combustion chamber that caused the fire,” said Gamba. “There was no explosion, nothing got damaged. One of the main challenges of these devices is the ignition. If the ignition is not properly tuned, sometimes it can be rocky. The ignition was a little bit more violent than usual (last night).”
Gamba said the club is predominantly made up of undergraduate students who are self-sustained and manage and operate the team independently. He and other faculty advisors help mentor the group and supervise their activities.
He said that the students focus on developing small-scale rockets, and that Thursday night’s blast wasn’t out of the ordinary.
“Everything was approved, reviewed and followed based on procedures,” he said. “The outcome -- including the response -- falls within procedure that was recognized and validated. Obviously, you don’t want a fire to escape, but those are the scenarios that are included in the development of the testing plans.”
As for relocating the students’ testing site away from a residential area, Gamba said the topic has been discussed and will continue to be discussed moving forward.
The University of Michigan released the following statement on Friday morning about the incident:
On April 29, at approximately 10:15 p.m., a student organization was conducting an experiment related to their academic studies. The experiment was conducted on university property near the west side of Green Road, south of Plymouth Road.
The experiment was conducted inside a container located in an open field. A failure occurred, causing a blast and a small fire inside the container, which was extinguished by the Ann Arbor Fire Department. There were no injuries and no property damage, other than to the container and contents.
A root cause analysis and review of safety protocols are being conducted by the U-M College of Engineering and the Department of Environment, Health and Safety.
Kennedy said the students were lucky to have walked away unscathed from such a large blast.
“The fact that there were no fatalities or injuries was remarkable given the fire and gas wave that was created in this incident,” he said. “There was indication that we had signed off on this and I very clearly want to state this was not the case. I would have significant concerns if this activity (continued) at this location.”